Choosing the ultrasonic frequency in control of weighted substances in manure waste of livestock facilities

The existing technological lines for wastewater treatment, primarily industrial pig farms, do not provide the required quality of the treated wastewater for its further biological treatment, which causes serious environmental pollution and creates a tense ecological situation around the location of livestock facilities. The problem of improving the quality of work of treatment facilities can be solved by using an ultrasonic control method based on a change in the absorption of sound waves depending on the concentration of suspended solids in a liquid medium. The overall absorption coefficient is complexly dependent on the ultrasound frequency and particle radius. The dependence of the absorption coefficient on concentration is linear, which simplifies the use of ultrasonic location for concentration control and increases the accuracy of measurements. The change in the absorption of ultrasonic waves passing through the medium under study should be in the range convenient for subsequent processing of the signal amplitude by the electronic unit of the measuring device. When choosing the optimal ultrasound frequency, the following parameters should be taken into account: the acoustic base of the sensor, particle size distribution of suspensions, and the required concentration control range. An increase in the acoustic base of the measuring sensor leads to decreasing in the required frequency of ultrasound for the considered parameters of suspended solids in effluents. To measure the concentration of suspended solids in the liquid phase after the primary and secondary clarifiers in the treatment plant, an ultrasound frequency of 2,4 to 4,6 MHz should be used, and for sediment in these clarifiers, a frequency of 1,7 to 3,2 MHz.